Sulfide Oxidation by O2: Synthesis Structure and Reactivity of Novel Sulfide-Incorporated Fe(II) Bis(imino)pyridine Complexes

摘要

The unsymmetrical iron(II) bis(imino)pyridine complexes [Fe^II(LN3SMe)(H2O)3](OTf)2 (>1), and [Fe^II(LN3SMe)Cl2] (>2) were synthesized and their reactivity with O2 was examined. Complexes >1 and >2 were characterized by single crystal X-ray crystallography, LDI-MS, ¹H-NMR and elemental analysis. The LN3SMe ligand was designed to incorporate a single sulfide donor and relies on the bis(imino)pyridine scaffold. This scaffold was selected for its ease of synthesis and its well-precedented ability to stabilize Fe(II) ions. Complexes >1 and >2 ware prepared via a metal-assisted template reaction from the unsymmetrical pyridyl ketone precursor 2-(O=CMe)-6-(2,6-(ⁱPr2-C6H3N=CMe)-C5H3N. Reaction of >1 with O2 was shown to afford the S-oxygenated sulfoxide complex [Fe(LN3S(O)Me)(OTf)]²⁺(>3), whereas compound >2, under the same reaction conditions, afforded the corresponding sulfone complex [Fe(LN3S(O2)Me)Cl]²⁺ (>4).